Lubricating oils containing amine salts of phosphates



United States Patent LUBRICATlNG OILS CONTAINING AMINE SALTS OF PHOSPHATES Edwin J. Latos, Chicago, and Anthony J. Guarnaccio,

'Niles, lll., assignors to Universal Oil Products Company, Des Plaines, llL, a corporation of Delaware No Drawing. Filed Mar. 22, 1962, Ser. No. 181,785

4 Claims. (Cl. 252-325) This invention relates to an oil of lubricating viscosity of improved properties.

The advancing technology in the mechanical field is accompanied by the need for improved operation of moving metal parts. As this technology advances, the moving parts are required to operate satisfactorily under more severe conditions including higher speeds, higher temperatures, greater loads, longer periods of use, etc. In aircraft, this increased severity also includes operation at higher altitudes. Moving parts inherently require lubrication and the advancing technology in the mechanical field of necessity requires correspondingly improved Inbricants. Great strides have been made in the art of lubrication as, for example, the more careful selection of the fraction and types of mineral oil used for lubrication, improved refining and treating of the mineral oils, development and use of synthetic lubricating oils, etc.

Even with the improved lubricating oils presently available, there is a constant need to further improve such oils. As these oils are further improved, the severity of the operation of the moving parts can be correspondingly increased, with the resultant improved efliciency of operation. One method of improving the properties of lubricating oils is by the incorporation of additives therein. The present invention is directed to the use of a novel additive to improve the properties of lubricating oils.

The present invention is used with any lubricating oil, which may be of natural or synthetic origin. The mineral oils include those of petroleum origin and are referred to as motor lubricating oil, railroad type lubricating oil,

marine oil, transformer oil, turbine oil, differential oil,

diesel lubricating oil, gear oil, cylinder oil, specialty products oil, etc. Other natural oils include those of animal, marine or vegetable origin.

Synthetic lubricating oils are of varied types including aliphatic esters, polyalkylene oxides, silicones, esters of phosphoric and silicic acids, highly fluorine-substituted hydrocarbons, etc. Of the aliphatic esters, di-(Z-ethylhexyl) sebacate is being used on a comparatively large commercial scale. Other aliphatic esters include dialkyl azelates, dialkyl suberates, dialkyl pimelates, dialkyl adipates, dialkyl glutarates, etc. Specific examples of these esters include dihexyl azelate, di-(2.-ethylhexyl) azelate, di-3,5,5-trimethylhexyl glutarate, di-3,5,5-trimethylpentyl glutarate, di-(Z-ethylhexyl) pimelate, di-(Z-ethylhexyl) adipate, triamyl tricarballylate, pentaerythritol tetracaproate, dipropylene glycol dipelargonate, 1,5-pentanedioldi-(2-ethylhexanonate), etc. The polyalkylene oxides ininclude polyisopropylene oxide, polyisopropylene oxide diether, polyisopropylene oxide diester, etc. The silicones include methyl silcone, methyphenyl silicone, etc., and the silicates include, for example, tetraisooctyl silicate, etc. The highly fiuorinated hydrocarbons include fluorinated oil, perfiuorohydrocarbons, etc.

Additional synthetic lubricating oils include (1) neopen tyl glycol esters, in which the ester group contains from 3 to 12 carbon atoms or more, and particularly neopentyl glycol propionates, neopentyl glycol butyrates, neopentyl glycol caproates, neopentyl glycol caprylates, neopentyl glycol pelargonates, etc., (2) trimethylol alkanes such as trimethylol ethane, trimethylol propane, trimethylol butane, trimethylol pentane, trimethylol hexane, trimethylol heptane, trimethylol octane, trimethylol decane, trimethylol undecane, trimethylol dodecane, etc., as well as the esters thereof and particularly triesters in which the ester portions each contain from 3 to 12 carbon atnrns and may be selected from those hereinbefore specifically set forth in connection with the discussion of the neopentyl glycol esters, and (3) tricresylphosphate, trioctylphosphate, trinonylphosphate, tridecylphosphate, as well as mixed aryl and alkyl phosphates, etc.

The present invention also is used in the stabilization of greases made by compositing one or more thickening agents with an oil of natural or synthetic origin. Metal base synthetic greases are further classified as lithium grease, sodium grease, calcium grease, barium grease, strontium grease, aluminum grease, etc. These greases are solid or semi-solid gels and, in general, are prepared by the addition to the lubricating oil of hydrocarbon soluble metal soaps or salts of higher fatty acids as, for example, lithium stearate, calcium stearate, aluminum naphthenate, etc. The grease may contain one or more thickening agents such as silica, carbon black, talc, organic modified bentonite, etc., polyacrylates, amides, polyamides, aryl ureas, methyl N-n-octadecyl terephthalomate, etc. Another type of grease is prepared from oxidized petroleum Wax, to which the saponifiable base is combined with the proper amount of the desired saponifying agent, and the resultant mixture is processed to produce a grease. Other types of greases in which the features of the present invention are usable include petroleum grease, whale grease, wool grease, etc., and those made from inedible fats, talloW, butchers waste, etc.

Oils of lubricating viscosity also are used as transmission fluids, hydraulic fluids, industrial fluids, etc., and the novel features of the present invention are used to further improve the properties of these oils. During such use the lubricity properties of the oil are important. Any suitable lubricating oil which is used for this purpose is improved by incorporating the additive of the present invention.

Oils of lubricating viscosity also are used as cutting oils, rolling oils, soluble oils, drawing compounds, etc. In this application, the oil is used as such or as an emulsion with water. Here, again, it is desired that the oil serves to lubricate the metal parts of saws, knives, blades, rollers, etc., in addition to dissipating the heat created by the contact of the moving metal parts.

Oils of lubricating viscosity also are used as slushing oils. The slushing oils are employed to protect finished or unfinished metal articles during storage or transportation from one area to another. The metal articles may be of any shape or form including steel sheets, plates, panels, coils, bars, etc., which may comprise machine parts, engines, drums, piston rings, light anns, etc., as well as farm machinery, marine equipment, parts for military or other vehicles, household equipment, factory equipment, etc. A coating which may be visible to the eye, or not, as desired, covers the metal part and protects it from corrosion, etc.

From the hereinbefore discussion, it will be seen that the present invention is directed to improving oils of lubricating viscosity which have a variety of uses. As mentioned above, the demand on lubricating oils is becoming more severe and is being met by the use of the improved additive. This increased severity is encountered, for example, in oils used for the lubrication of hypoid gears because of the high contact pressures encountered. More recent developments are directed to the extremely long time use of such oils as, for example, in the break-in or run-in oil used in automobile differential systems, during which period the gears are extremely susceptible to surface damage. The oil must protect the gear surfaces during the high torque-low speed, low torque-high speed and high torque-high speed conditions. Furthermore, it is not necessary to change the oil after the break-in period,

and the oil then is expected to operate satisfactorily for one year or more and 20,000 miles or more of operation. In addition to retaining its lubricity properties, it is also desired to avoid corrosion of the metal parts and also to avoid the formation of deposits which could interfere with satisfactory operation. While the novel additives of the present invention are particularly useful in oils of lubricating viscosity required for more severe use, it is understood that the improved benefits also are obtained in oils of lubricating viscosity which are used under less severe conditions.

We have found that the amine salts of oxyalkylenated hydroxycarbon phosphates are effective additves for oils of lubricating viscosity. However, these amine salts have certain disadvantages which may affect their optimum use in many applications. It has been observed that these amine salts are detrirnentally affected by water which appears to decrease the lubricity properties of the additive. The present invention provides a novel mixture including these amine salts which are not detrimentally affected by water.

Another disadvantage to the use of the amine salts of oxyalkylenated hydroxyhydrocarbon phosphates is that they are not soluble to a desired degree in highly parafiinic oils and, therefore, require an extraneous solubilizing agent. As another advantage to the novel mixture of the present invention, the mixture is readily soluble in such highly paraflinic oils and does not require the need of an extraneous solubilizing agent.

In one embodiment the present invention relates to an oil of lubricating viscosity suitable for use as lubricating oil, transmission fluid, cutting oil and slushing oil comprising a major proportion of lubricating oil and a small but stabilizing proportion of a mixture of (1) amine salt of oxyalkylenated hydroxyhydrocarbon phosphate and- (2) amine salt of alkyl acid phosphate.

In a specific embodiment the present invention relates to a lubricating oil containing a small but stabilizing proportion of (1) diamine salt of polyoxyethylenated alkylphenol phosphate and (2) diamine salt of mixed monoand di-alky acid phosphate containing at least 8 carbon atoms.

Ashereinbefore set forth, the novel additive of the present invention is a mixture of (1) an amine salt of an oxyalkylenated hydroxyhydrocarbon phosphate and (2) an amine salt of an alkyl acid phosphate.

AMINE SALT OF OXYALKYLENATED HYDROXY- HYDROCARBON PHOSPHATE The amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate is illustrated by the following general formula:

where O is oxygen, P is phosphorus, H is hydrogen, n is an integer of from 1 to 40, R is a hydrocarbon group, R is alkylene, A is amine, B is selected from the group consisting of hydrogen, the same as the bracketed group, and the same as A.

The general formula hereinbefore set forth also may be illustrated as follows:

where the symbols have the same meaning as set forth above, N is nitrogen, R is selected from the group consisting of a hydrocarbon and a substituted hydrocarbon group, and R is selected from the group consisting of 4 hydrogen, a hydrocarbon and a substituted hydrocarbon grou In a preferred embodiment R is selected from alkylphenyl and aliphatic groups. In the alkylphenyl species, 1, 2 or 3 alkyl groups of from 4 to 30 and, more particularly, from 6 to 15 carbon atoms each, will be attached to the phenyl ring. Illustrative preferred alkylphenyl groups include hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl, tetradecylphenyl, pentadecylphenyl, etc., dihexylphenyl, diheptylphenyl, dioctylphenyl, dinonylphenyl, didecylphenyl, diundecylphenyl, didodecylphenyl, etc., trihexylphenyl, triheptylphenyl, trioctylphenyl, trinonylphenyl, tridecylphenyl, etc. In another embodiment the alkylphenyl radical may contain one or more alkyl groups containing 4 to 30 carbon atoms and one or more alkyl groups containing less than 4 carbon atoms and selected from methyl, ethyl and propyl. When one alkyl group is attached to the phenyl ring, it preferably is in the position para to the oxygen. When two alkyl groups are attached to the phenyl ring, they preferably are in the 2,4- or 3,5-positions.

Where R is an aliphatic group, it preferably contains from 6 to 40 carbon atoms and, more particularly, from I 10 to 30 carbon atoms. Illustrative preferred aliphatic groups include decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl, triacontyl, etc. In general, it is preferred that the aliphatic group is saturated. In another embodiment, the aliphatic group may be unsaturated and will be selected from olefinic radicals corresponding to the saturated radicals hereinbefore specifically set forth. The aliphatic group may be straight chain or may contain branching in the chain.

R in Formulas 1 and 2 is an alkylene group and may contain from 1 to 10 and preferably from 2 to 4 carbon atoms per group. The preferred alkylene radicals thus are ethylene, propylene and butylene. As hereinbefore set forth, n is an integer of from 1 to 40 and preferably of from 2 to 12.

Referring to Formulas 1 and 2, when E is hydrogen or the same as A, this component of the mixture comprises the amine salt of the mono-(alkylenated hydroxyhydrocarbon) phosphate. When B in the above general formula is the same as the bracketed group (oxyalkylenated hydroxyhydrocarbon), the salt comprises the amine salt of the di-(alkylenated hydroxyhydrocar-bon) phosphate. It is understood that a mixture of the amine salt of the mono(alkylenated hydroxyhydrocarbon) phosphate and of the amine salt of the di-(alkylenated hydroxyhydrocarbon) phosphate may be employed and also that a mixture of dilferent amines may be used in preparing these additives.

Any suitable amine may be used and contains from 2 to 50 carbon atoms or more and preferably from 8 to 20 carbon atoms. The amine may be a monoamine or polyamine. Preferred monoamines include octyl amine, nonyl amine, decyl amine, undecyl amine, dodecyl amine, tridecyl amine, tetradecyl amine, pentadecyl amine, hexadecyl amine, heptadecyl amine, octadecyl amine, nonadecyl amine, eicosyl amine, etc. The amines may be prepared from fatty acid derivatives and, thus, may comprise tallow amine, hydrogenated tallow amine, lauryl amine, coconut amine, soya amine, etc.

Of the polyamines, N-alkyl diaminoalkanes are preferred. A particularly preferred amine of this class cornprises an N-alkyl-1,3-diaminopropane in which the alkyl group contains from about 8 to about 25 carbon atoms. A number of N-alkyl diaminoalkanes of this class are available commercially, such as Duomeen T and Diam 26 in which the alkyl group is derived from tallow and contains from about 12 to about 20 carbon atoms per group, and mostly 16 to 18 carbon atoms. Other N-alkyl- 1,3-diaminopropanes may be prepared to contain any number of carbon atoms desired in the alkyl group and thus the alkyl group is selected from hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc.

While the N-alkyH,3-diaminopropanes are preferred, it is understood that other suitable N-alkyl diaminoalkanes may be employed. Illustrative examples include N-alkyll ,Z-diaminoethane, N-alkyl-1,2-diaminopropane, N-alkyl-l ,Z-diaminobutane, N-alkyl- 1 ,3-diaminobutane, N-alkyll ,4-diaminobutane, N-alkyl-1,2-diaminopentane, N-alkyl-1,3-diaminopentane, Nalkyl-1,-4diaminop entane, N-alkyl-1,5-diaminopentane, N-alkyl-1,2-diaminohexane, N-alkyl-1,3-diaminohexane, N-alkyl-1,4-diaminohexane, N-alkyl-l ,S-diaminohexane, N-alkyl-1,6-diaminohexane, etc.

Other polyamines include ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octylenediamine, etc., diethyltriamine, dipropylenetriamine, dibutylenetriamine, etc., triethylenetetramine, tripropylenetetramine, tributylenetetramine, etc., tetraethylenepentamine, tetrapropylenepentamine, tetrabutylenepentamine, etc.

In another embodiment the amine is an aromatic amine. Monoamines include aniline, toluidines, xylidines, etc., napthylamine, anthracylamine, rosin amine, etc., as Well as the N-monoand N,N-di-alkylated aromatic amines in which the alkyl group or groups contain from 1 to carbon atoms or more. Illustrative examples of such compounds include N-methylaniline, N,N-di-methylaniline, N-ethylaniline, N,N-di-ethylaniline, N-propylaniline, N,N-dipropylaniline, N-butylaniline, N,N-dibutylaniline, N-amylaniline, N-hexylaniline, N-heptylaniline, N-octylaniline, N-nonylaniline, N-decylaniline, N- undecylaniline, N-dodecylaniline, etc., as Well as the corresponding substituted toluidines, xylidines, naphthylamines, anthracylamines, etc.

In still another embodiment the amine may contain halogen as, for example, in compounds such as chloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 2,5-dichloroaniline, 2,6-dichloroaniline, 3,4-dichloroaniline, 3,5- dichloroaniline, bromoaniline, dibromoaniline, etc.

In another embodiment the aromatic amine is an diarylamine including, for example, diphenylamine, aminodiphenylamine, diaminodiphenylamine, dinaphthylarnine, aminodinaphthylamine, diarninodinaphthylamine, etc. In the polyamino aromatic compounds, the nitrogen atoms may be in the position ortho, meta or para to each other. The amino or diaminodiphenyl amines may contain alkyl groups attached to one or both nitrogen atoms and the alkyl groups may contain from 1 to or more carbon atoms each. Illustrative compounds include p,p'-di-methylaminodiphenylamine, p,p-di-ethylaminodiphenylamine, p,p-di-propylaminodiphenylamine, p,p'-di-butylaminodiphenylamine, p,p'-di-amylaminodiphenylamine, p,p'-di-hexylaminodiphenylamine, p,p'-di-heptylaminodiphenylamine, p,p'-di-octylaminodiphenylamine, p,p'-di-nonylaminodiphenylamine, p,p'-di-decylaminodiphenylamine, etc., o,p-di-methylamino diphenylamine, o,p-di-ethylaminodiphenylamine, o,p'-di-propylaminodiphenylamine, o,p'-di-buty1aminodiphenylamine,

o,p'- 1i-amylaminodiphenylamine, o,p'-di-hexylaminodiphenylamine, o,p-di-heptylaminodiphenylamine, o,p'-di-octylaminodiphenylamine, o,p'-di-nonylaminodiphenylamine, o,p'-di-decylaminodiphenylamine, etc., N-alkyldiaminodiphenylamine, N,N,N'-trialkyldiarninodiphenylamine, N,N,N,N'-tetralkyldiaminodiphenylamine, etc.

In still another embodiment the amine comprises such compounds as amin-odiphenylether, N-alkylaminodiphenylether, N,N'-dialkylarninodiphenylether, N,N,N'-tn'alkylaminodiphenylether, N,N,N',N'-tetralkylaminodiphenylether, aminodiphenylsulfide, N-alkylaminodiphenylsulfide, N,N'*dialkylaminodiphenylsulfide, N,N,N-trialkylaminodiphenylsulfied, N,N,N',N'-tetralkylaminodiphenylsulfied, aminodiphenylmethane, N-alkylaminodiphenylmethane, N,N'-diakylaminodiphenylmethane, N,N,N'-trialkylaminodiphenylmethane, N,N,N,N'-tetralkylaminodiphenylmethane, aminodiphenylethane, N-alkylaminodiphenylethane, N,N'-dialkylaminodiphenylethane, N,N',N-trialkylaminodiphenylethane, N,N,N,N'-tetralkylaminodiphenylethane, aminodiphenylpropane, N-alkylaminodiphenylpropane, N,N-dialkylaminodiphenylpropane, N,N,N-trialkylaminodiphenylpropane, N,N,N',N'-tetralkylarninodiphenylpropane, aminodiphenylbutane, N-alkylaminodiphenylbutane, N,N'-dialkylaminodiphenylbutane, N,N,N-tr-ialkylaminodiphenylbutane, N,N,N',N'-tetralkylaminodiphenylbutane, etc., in which the alkyl group or groups contain from 1 to 20 or more carbon atoms each.

In still another embodiment the amine may comprise an alkanol amine including such compounds as ethanol amine, diethanol amine, propanol amine, dipropanol amine, butanol amine, dibutanol amine, pentanol amine, dipentanol amine, hexanol amine, dihexanol amine, etc., and N-alkylated and N,N-dialky1ated alkanol amines in Which the alkyl group or groups contain from 1 to 20 or more carbon atoms each. In still another embodiment the amine may comprise an aminophenol including, for example, p-aminophenol, o-aminophenol, m-aminophenol, 2,6-dimethyl-p-arninophenol, 2,6-diethy1-p-aminophenol, 2,6-diisopropyl-p-aminophenol, 2,6-disecbutyl-p-aminophenol, 2,6-disecamyl-p-aminophenol, 2,6-disechexyl-p-aminophenol, etc., 4-N,N-dimethylam ino-2,6 diisopropylphenol, 4-N,N-dimethylamino-2,6-disecbutylphenol, etc., 4-N,N-dimethylaminomethyl-Z,6-diisopropylphenol, 4-N,N-dimethylaminomethyl-Z,6-disecbutylphenol, 4-N,N-diethylaminomethyl-Q,6-diisopropylphenol, 4-N,N-diethylaminomethyl-2,6-disecbutylphenol, 4-N,N-dipropylaminomethyl-Z,6-diisopropylphenol, 4-N,N-dipropylaminomethyl-Z,6-disecbutylphenol, 4-N,N-dibutylaminomethyl-Z,6 diisopropylphenol, 4-N,N-dibutylaminomethyl-Z,6-disecbutylphenol, 4-N,N-diethylaminoethyl-2,6-diisopropylphenol, 4-N,N-diethylaminoethyl-2,6-disecbutylpheno1,

7 4-N,N-dipropylaminopropyl-2,6-diisopropylpheno1, 4-N,N-dipropylaminopropyl-2,6-disecbutylphenol, 4-N,N-di'butylaminobutyl-Z,6-diisopropylphenol, 4-N,N-dibutylaminobutyl-2,6-disecbutylphenol, etc.

It is understood that a mixture of amines may be employed and that the different amines are not necessarily equivalent.

The amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate is prepared in any suitable manner. In a preferred method, the hydroxyhydrocarbon, including particularly :alkylphenol or aliphatic alcohol, is oxyalkylenated by reacting with alkylene oxide, incuding particularly ethylene Xide,.ir1 the molar ratios to produce an oxyalkylenated hydroxyhydrocarbon containing the oxyalkylene group in the desired proportion. As hereinbefore set forth, in a preferred embodiment the additive contains from 2 to 12 oxya'lkylene groups. More particularly, the number of oxyalkylene groups is from 2 to 6. The oxyalkylenation is effected in any suitable manner and generally will be conducted at a temperature of from about room temperature to about 350 F. and preferably from about 200 F. to about 300 P1, preferably in the presence of a catalyst such as sodium hydroxide, potassium hydroxide, tertiary amine, quarternary hydroxide, etc. When the oxyalkylenation is to be limited to the addition of one oxy group, the catalyst may be omitted and the reaction is effected in the presence of water. Superatmospheric pressure may be employed, which may range from to 1000 pound or more.

The oxyalkylenated hydroxyhydrocarbon then is reacted in any suitable manner with P 0 to form the desired phosphate. One molar proportion of P 0 is reacted per one or two molar proportions of the oxyalkylenated hydroxyhydrocarbon. In general, an excess of P 0 is employed in order to insure complete reaction. The reaction is effected at a temperature ranging from room temperature to about 230 F. and under substantially anhydrous conditions. The resultant free acid form of the Phosphate generally is recovered as a viscous liquid.

The amine salt is prepared in any suitable manner and is readily prepared by slowly adding the amine to the free acid form of the phosphate with intimate stirring. When the amine is a solid, it may be heated to melt the same. The reaction is effected at any suitable temperature, and preferably as low as practical. The temperautre, therefore, preferably is within the range of from room temperature to 250 F. and more particularly to 150 F. In general, the neutral salt is preferred and is prepared by using equivalent amine and acid groups. Accordingly, this will depend upon whether a monoamine or polyamine is used and whether the monoor di(alkylenated hydroxyhydrocarbon phosphate) is used in preparing the salt. When the basic salt is desired, an excess of amine per acid group will be used and, when the acid salt is desired, a deficiency of amine per acid group is employed in forming the salt. Generally the amine salt will be recovered as a viscous liquid.

AMINE SALT OF ALKYL ACID PHOSPHATE The amine salt of the alkyl acid orthophosphate is illustrated by the following general formula:

where O is oxygen, P is phosphorus, H is hydrogen, R is a hydrocarbon group, A is amine and B is selected from the group consisting of hydrogen, the same as R and the same as A.

The general formula herein'before set forth also may be illustrated as follows:

where the symbols have the same meaning as set forth above, N is nitrogen, R" is selected from the group consisting of a hydrocarbon and a substituted hydrocarbon group, and R' is selected from the group consisting of hydrogen, a hydrocarbon and a substituted hydrocarbon group.

Formulas 3 and 4 illustrate the monoand dialkyl acid orthophosphates. Also included for use in the present invention are the alkyl acid pyrophosphates and includes the monoalkyl ester, dialkyl ester, trialkyl ester or mixtures thereof. The dialkyl ester is preferred and the ester groups may be attached to the same or different phosphorus atom. Generally, however, this compound will be symmetrical and, thus, the alkyl ester groups will be attached to different phosphorus atoms. It is understood that both the alkyl acid orthophosphates and alkyl acid pyrophosphates are included in the term alkyl acid phosphate as used in the present specifications and claims.

In a preferred embodiment, R in Formulas 3 and 4 is an aliphatic group and preferably contain at least 5 carbon atoms. It may contain from 5 to 40 carbon atoms and, more particularly, from 5 to 20 carbon atoms. Illustrative preferred alkyl groups include amyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc. In general, it is preferred that the aliphatic group is saturated. In another embodiment, the aliphatic group may be unsaturated and will be selected from olefinic radicals corresponding to the saturated radicals hereinbefore specifically set forth. The aliphatic group may be straight chain or may contain branching in the chain.

As hereinbefore set forth, this component of the additive mixture is an amine salt of the alkyl acid phosphate.

Any suitable amine may be used and contains from 2 to 50 carbon atoms or more and preferably from 8 to 20 carbon atoms. The amine may be a monoamine or polyamine and is selected from the amines hereinbefore specifically set forth in connection with the description of the amines used in the preparation of the amine salts of the oxyalkylenated hydroxyhydrocarbon phosphates. Particularly preferred amine salts include, as representative of the monoam-ines, tallow amine, hydrogenated tallow amine, lauryl amine, coconut amine, soya amine, etc. and, as representative of the polyamines, Duomeen T or Diam 26 and N-alkyl-l,3-diaminopropanes in which the alkyl group is derived from high molecular weight fatty :acids. In the interest of brevity, the specific amines for use in preparing the amine salt of the alkyl acid phosphate is not repeated here, but it is understood that it is selected from those specifically 'hereinbefore set forth in connection with the description of the amine used in preparing the amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate.

The amine salt of the alkyl acid phosphate is prepared in any suitable manner and, in general, is prepared by slowly adding the amine to the alkyl acid phosphate at ambient temperature, preferably with vigorous stirring. The salt is readily prepared at room temperature, although slightly elevated temperatures which generally will not exceed about 250 F. may be employed. When desired, a solvent may be used, either in forming a more fluid mixture of the acid and/ or amine before mixing or during the mixing thereof. Any suitable solvent may be used and generally will comprise an organic compound and, more particularly, an aromatic hydrocarbon or mixture of hydrocarbons including benzene, toluene, xylene,

ethylbenzene, straight run naphtha, cracked naphtha, reformed naphtha, etc.

In general, the acid salt of the amine and alkyl acid phosphate is preferred. The acid salt is prepared by using an excess of acid with relation to the amine as, for example, two equivalent of acid per one equivalent of amine. In another embodiment, the neutral salt is used and is prepared by utilizing stoichiometric amounts of the amine and the acid. In other words, the concentration of amine and of alkyl acid phosphate will be selected so that there will be an equivalent number of amine groups to acid groups. Thus, the specific concentrations will depend upon whether the ortho or pyrophosphate salt and upon whether a monoamine or polyarnine is employed. In another embodiment, the salt is a basic salt, which is prepared by utilizing a deficiency of acid groups in relation to the amino groups as, for example, by utilizing one equivalent of acid per two equivalent of amine. It is understood that the different salts are not necessarily equivalent.

The preparations set forth above describe the separate formation of the amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate and of the amine salt of the alkyl acid phosphate. When desired, these amine salts may be prepared simultaneously by commingling the oxyalkylenated hydroxyhydrocarbon phosphate and the alkyl acid phosphate and then adding the amine in the proper proportion to the mixture of phosphates, with vigorous stirring. Here, again, the reaction is effected at a temperature ranging from ambient to about 250 F. and the mixed salts are recovered as a viscous liquid. 1

The amine salt of oxyalkylenated hydroxyhydrocarbon phosphate and the amine salt of alkyl acid phosphate are used in any suitable proportions to obtain the improved results of the present invention. These proportions may range from 5% to 95% by weight of one salt and 95% to 5% by weight of the other salt. Generally, however, the proportions of these salts will be in the range of from to 90% by weight of one salt and 90% to 10% by weight of the other salt. In a preferred embodiment, the salts are used in a proportion of 30% to 70% by weight of one salt and 70% to 30% by weight of the other salt. In one embodiment the amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate is used in a major proportion and, in another embodiment, the amine salt of the alkyl acid phosphate is used in a major proportion.

While the use of the mixture of the amine salt of oxyalkylenated hydroxyhydrocarbon phosphate and amine salt 'of the alkyl acid phosphate is preferred, in another embodiment the amine salt of the alkyl acid phosphate may be employed in admixture with the oxyalkylenated hydroxyhydrocarbon phosphate and, in still another embodiment, the amine salt of the oxyalkylenated hydroxyhydrocarbon phosphate may be utilized in admixture with the alkyl acid phosphate. In these embodiments, the amine salt of only one of the phosphates is prepared and such salt is used in admixture with the other phosphate. It is quite probable that, after mixing, the amine may migrate to the other phosphate and result in a mixture of the amine salts of both phosphates, with some free phosphate remaining in the mixture. In still another embodiment, the mixture may contain an excess of amine.

As hereinbefore set forth, the additive composition of the present invention is incorporated in an oil of lubricating viscosity. Lubricating oils generally have a viscosity within the range of from 10 SUS at 100 F. to 1000 SUS at 210 F. (SAE viscosity numbers include the range from SAE 10 to SAE 160). The petroleum oils are obtained from paraflinic, naphthenic, asphaltic or mixed base crudes.

The novel additive mixture of the present invention is used in a small but stabilizing concentration in the oil of lubricating viscosity. Depending upon the particular use, the additive composition may be employed in a concentration of from about 0.01% to about 25% and preferably from about 0.5% to 10% by weight of the oil. When used in conventional lubricating oil, the additive composition may be employed in a concentration of from about 0.01% to about 2% by weight of the oil. When used in lubricating oil for more severe operations, such as hypoid gear oil, the additive composition is used in a concentration of from about 1% to about 20% or more by weight of the oil. In general, substantially the same range of additive concentration is employed when the oil is used as transmission fluid, hydraulic fluid, industrial fluid, etc. When the oil is used in the formulation of a grease, the additive composition is used in a concentration of from about 0.5 to 5% by weight of the oil. When used in cutting oil, rolling oil, soluble oil, drawing compound, etc., the additive composition may be used in a concentration of from about 0.1% to about 10% by weight of the oil. When used in slushing oil, the additive composition may be used in a concentration of from about 0.1% to about 15% by weight or more.

of the oil.

It is understood that the additive composition of the present invention may be used along with other additives incorporated in the oil for specific purposes. In most cases, it is desirable to also incorporate an antioxidant in the oil. Preferred antioxidants are of the phenolic type and include tertiarybutylcatechol, 2,6-ditertiarybutyl-4-methylphenol, 2,4 dimethyl 6 tertiarybutylphenol, etc., 2 tertiarybutyl 4 methoxyphenol, 2- 'terti-arybutyl-4-ethoxyphenol, etc. Also, other additives incorporated in lubricating oil include metal deactivator, dye, viscosity index improver, pour point depressor, antifoaming additive, etc.

As hereinbefore' set forth, the additive composition of the present invention possesses emulsifying properties and, therefore, will serve to emulsify water and oil of lubricating viscosity for use as lubricating oil, slushing oil, cutting oil, rolling oil, soluble oil, drawing compound, etc. When desired, an additional emulsifying agent may be employed. Any suitable emulsifying agent can be used, including alkali metal sulfonates of petroleum sulfonic acids, mahogany sulfonates, napthenic acids, fatty acids, etc., fatty alcohol sulfonates pentaerythritol 'oleates, laurates, etc. The amount of water used in the emulsified oils will depend upon the particular use of the emulsion and may range from 0.25% to 50% or even up to 98% by weight of the composition.

The following examples are introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

As hereinbefore set forth, the novel additive composi tions of the present invention serve to stabilize the lubricity properties of the oil of lubricating viscosity, and the effectiveness of additives for this purpose has been determined in a modified Bowden-Leben pin and disc machine. The Bowden-Leben method is described in The Friction and Lubrication of Solids, 1954, page 74, by Bowden and Tabor. This method is also discussed in the article by E. Rabinowicz entitled The Boundary Friction of Very Well Lubricated Surfaces, which was presented at the A.S.L.E. Ninth Annual Meeting in Cincinnati on April 5, 1954, and published in the July-August 1954 issue of Lubricating Engineering. In the modification used for the runs reported herein, a highly polished steel disc rotates in contact with an upwardly extended rounded steel pin. The pin and disc vthen are immersed in a pan containing the oil to be evaluated. The equipment is enclosed in a housing which is heated for varying the temperature of the run which, in these experiments, ranged from 72 to 350 F. The equipment also includes a variable speed reducer for varying the r.p.m. of the disc and also means for varying the load. In each run the wear or break-in period consists of gradually increasing the speed to 196 r.p.m. at 2000 g. load and decreasing the speed to 12 rpm. after which the speed is increased to 196 r.p.m. The load varied from 500 g. to 2000 g. and the coeflicient of friction was determined at r.p.m.s decreasing from 196 to 0.1. A strain gage circuit is used as sensing element in converting the frictional effects into equivalent electrical responses which then are recorded on a continuous chart recorder. The highest coefficient of friction is reported for each run. In addition, the diameter of the wear spot on the pin is measured. The pin, disc and pan are visually inspected immediately after the test to determine visible corrosion and also to determine whether deposit formation has occurred.

The oil of lubricating viscosity used in the runs reported in the following examples is a commercial white oil sold by A. H. Carnes Company as Games 340 White Oil. Typical specifications of this oil include the following:

Distillation range, F. 740-975 Specific gravity at 60 F 0.8836 Viscosity:

At 100 F., S.U.S. 360 At 210 F., S.U.S. 52.2

Flash point, COC, F. 440

The additive composition of this example is a mixture of Duomeen T salt of polyoxyethylenated nonyl-phenol phosphate containing an average of about oxyethylenated groups and the Duomeen T salt of mixed monoand di-octyl acid orthophosphate. As hereinbefore set forth, Duomeen T is N-tallow-l,3-diaminopropane containing predominantly 16 to 18 carbon atoms in the alkyl group. The polyoxyethylenated nonylphenol phosphate is prepared in the manner as hereinbefore described. The neutral salts were prepared by utilizing the Duomeen T in an amount corresponding to the acid equivalents of the two phosphates. The mixed amine salts were prepared in a single step by commingling at room temperature 250 g. of polyoxyethylenated nonylphenol phosphate with 250 g. of the mixed monoand di-octyl acid orthophosphate and then gradually commingling 220 g. of Duomeen T thereto, with vigorous stirring. The Duomeen T was heated to a temperature of about 110 F. before adding to the mixture of phosphates. A slight temperature increase to about 175 F. occurred during the reaction. The above mixture comprised 50% by weight of each of the amine salts and was recovered as a reddish viscous liquid having the following physical properties:

Specific gravity at 60 F. 1.0028

Viscosity:

25 orous, stirring to the mixture of phosphates.

12 Example 11 144 g. of Duomeen T were heated to about 110 F. and

then were added gradually to the mixed phosphates, with continuous stirring. Heat was generated upon mixing. The mixed amine salts were recovered as a reddish viscous liquid.

Example III The basic amine salts of polyoxyethylenated nonylphenol phosphate and mixed monoand di-isooctyl orthophosphate were prepared as follows: 50 g. of polyoxyethylenated nonylphenol phosphate and 50 g. of mixed monoand di-isooctyl acid orthophosphate were commingled at room temperature. Duomeen T was heated to about 110 F. and 48.4 g. thereof were added with vig- The amine in this preparation was used in a 10% excess over the amount stoichiometrically required to form the neutral salts.

Example IV The lubricity properties of the Games 340 White Oil, with and without additives, were evaluated in the manner described above. The following table reports the results of evaluating a sample of the Carries 340 White Oil not containing an additive of the present invention (Run No. 1) and may be considered as a blank or control run. Run No. 2 reports the results of a sample of the same oil containing 1% by weight of the additive composition of Example I.

As hereinbefore set forth, an advantage of the additive composition of the present invention is that it is not adversely affected by water. Run No. 3 in the following table reports the results of a run with another sample of the Games 340 White Oil containing 1% by weight of the additive of Example I and 1% by weight of water.

As hereinbefore set forth, the additive composition of the present invention also may contain an anti-oxidant. The antioxidant used in Runs No. 4 and 5 is 2,6-ditertiarybutyl-4-methylphenol. The amount of anti-oxidant used in these runs is excessive, but was used in such a large concentration in order to be sure that the antioxidant does not exert any harmful effects. Run No. 4 was made with another sample of the Games 340 White Oil containing 1.5% by weight of the additive composition of Example I containing the antioxidant. Run No. 5 was made with At 100 F .U 24,749 1.5% by weight of the same additive mixture, but also At 210 F., S.U.S. 1,170 contained 1% by weight of water in order to determine Flash point, COC, F. 340 whether this mixture was adversely affected by water. Pour point, F. 25 The results of these runs are reported in the following Refractive index at 20 C 1 47744 table.

TABLE I Coefiicient of boundary friction Area of wear spot on pin, mm. Run Water Deposit No. present formation 72 F F. F. 200 F. 250 F. 300 F. 350 F Original Final Difference 1 No 0.1s-s 0. 24-s 0.24-s 0. 24-8 0. 24-s 0. 24-s 0.102 0. 035 0. 552 Some. 2 N0 0. 09 0. 09 0. 00 0.08 0. 04 0. 055 0.102 0. 047 None 3 Yes 0 00 0. 00 0.10 0.102 0.159 0.057 Do 4 N0 10 0.09 0.11 0.11 0.025 0.159 0 134 Do 5 Yes"--- 0 07 0.09 0.150 0 159 Do As hereinbefore set forth, Run No. 1 is the blank or control run of the oil without an additive of the present invention. The S indicates slip stick of seizure. Accordingly, it will be noted that the uninhibited oil was unsatisfactory for use under the conditions of the evaluations.

The results in Run No. 2 made with the oil containing the additive composition of Example I showed no seizure during the complete temperature range and, in fact, had a very low coefiicient of friction. The area of wear was very low in contrast to the 0.532 mm. difference in the control run. Also, it will be noted that there was no deposit formation in Run No. 2, whereas there was some deposit formed in Run No. 1.

As hereinbefore set forth, Run No. 3 was made in the presence of 1% by weight of water. It will be noted that the water had substantially no effect on the lubricity properties of the additive composition, and also that the area of wear was very low. Here again, no deposit formation was observed.

Runs 4 and 5 show that the additive composition containing the antioxidant also was very efiective in maintaining the lubricity properties of the oil and that this composition was not adversely affected by water.

Example V This example reports the results of evaluations made in the Games 340 White Oil using 1% by weight of the additive composition of Example HI. The following table also reports results made with the same additive composition in the Games 340 White Oil to which 1% by weight of water was added. These evaluations were made in the same manner as hereinbefore described. For comparison purposes, the data of Run No. 1 are re- 14 The steel panel dipped in the above oil not containing an inhibitor undergoes visible corrosion in less than one hour. The following table reports results of evaluations made using diiferent samples of the oil containing 1% by 5 weight of the additives of the present invention.

From the data in the above table, it will be seen that the 5 additive compositions reported above were very etfective in retarding corrosion.

Example VII The additive composition of this example is a mixture of 75% by weight of the p,p-N,N'-di-sec-butylaminodiphenylmethane neutral salt of the polyoxyethylenated nonylphenol phosphate and by weight of the acid salt of the mixed monoand di-isoamyl acid pyrophos- 25 phate neutral salt of N-soya-1,3-diaminopropane. Each salt was prepared separately by adding the amine to the phosphate at ambient temperature, with vigorous stirring. Following the preparation of each of the amine salts, the salts then were blended together in the proportions of 75 and 25 by Weight as hereinbefore set forth,

and the mixture was intimately stirred. The final mixture was recovered as a dark heavy viscous liquid.

The mixed amines prepared in the above manner are used in a concentration of 1% by weight in lithium peated in the table. grease. The grease is prepared by mixing 91% of a TABLE II Coefficient of boundary friction Area of wear spot on pin, mm. Run Water present 72 F. 100 F. 150 F. 200 F. 250 F. 300 F. 350 F Original Final Difference Here again, it will be noted that the additive composition of the present invention was very eifective in stabilizing the lubricity properties of the oil and also in reducing the area of wear. Also, it will be noted that the additive composition was not adversely atfected by the presence of water.

Example VI As hereinbefore set forth, in addition to stabilizing the lubricity properties of the oil, it is desirable that the additive composition also serves to retard corrosion. The corrosion inhibiting properties of additive compositions of the present invention were evaluated in the Humidity Cabinet Method. In this method, a highly polished steel panel is dipped into a viscous mineral oil, excess oil is drained, and the panel is placed in a humidity cabinet maintained at 120 F. in an atrnosphere saturated with water. The panels are rotated slowly and the time required for visible corrosion to appear on the panel is reported.

The oil used in these tests is Parafiin Oil No. 11 marketed by the American Oil Company. Typical specifications of this oil include the following:

Gravity, API 26.5-29.5. 70 Viscosity:

At 100 F., SUS 100410.

At 210 F., SUS 39.6. Flash point, COC, F. 350 min.

Pour point, F. 10 max.

50 ing and, at this temperature, 1% by weight of the additive composition of the present invention is added. Agitation is continued and the mixture then is allowed to cool to about 250 F. and finally cooled slowly to room temperature.

Example VIII The additive composition of this example is a mixture of 65% by Weight of the neutral salt of N,N-bis- (1- methylheptyl)-ethylenediamine and polyoxyethylenated nonyphenol phosphate and 35% by weight of the neutral salt of mixed monoand dioctyl acid pyrophosphate and N-tallow-1,3-diaminopropane. The mixed salts are prepared separately and then are commingled and intimately stirred.

The mixed amine salt composition prepared in the above manner is used in concentration of 3% by weight as an additive in transmission oil. The transmission oil is a solvent extracted lubricating oil having a viscosity of 150 SSU at 1009 F. and 44 SSU at 200 F. (viscosity index 95).

Example IX The additive composition of this example is a mixture of 50% by weight of the rosin amine salt of polyoxyethylenated nonylphenol phosphate and 50% by rately prepared and then are commingled at room temperature and intimately stirred. The final mixture is recovered. as a dark heavy viscous oil.

Example X The additive composition of this example is a mixture of 70% by weight of the hydrogenated tallow amine neutral salt of mixed monoand di-dodecyl acid orthophosphate and 30% by weight of the 2,5-dichloroaniline salt of the polyoxyethylenated nonylphenol phosphate. Each salt is separately prepared and then the two salts are mixed at room temperature with intimate stirring.

The final mixture is recovered as a heavy viscous oil.

Example XI phates. The mixture is stirred for 0.5 hour and the final mixture is recovered as a dark heavy viscous oil.

Example XII The additive composition of this example is 50% by weight of the neutral salt of Duomeen T and polyoxyethylenated nonylphenol phosphate containing 3 oxyethylene groups and 50% by weight of the neutral salt of Duomeen T and mixed monoand di-tridecyl acid orthophosphate. The salt is prepared by commingling the two phosphates at room temperature and then adding the Duomeen T in a sufiicient concentration to form the neutral salts of both phosphates.

One percent by weight of the additive composition prepared in the above manner is added to an oil used commercially as a lubricant during the rolling of steel. The oil has an API gravity of 272, a boiling range .of about 566" to about 700. F. and a SUS viscosity at 100 F. of 58.9.seconds.

Example XIII The additive composition of this example is 80% by weight of the neutral Duomeen T salt of polyoxyethylen-ated d-odecylphenol phosphate containing 8 oxyethylene groups and 20% by weight of the neutral Duomeen T salt of monoand diisopropyl acid orthophosphate. The mixed salts are prepared in substantially the same manner as hereinbefore set forth.

The additive composition prepared in the above manner is used in a concentration of 2% by weight in a slushing oil composition comprising lubricating oil having an API gravity of 24.5 a pour point of 60 F., a flash point, COC, of 320 F. and a viscosity at 100 F.

.of 106 SUS. Steel panels are dipped into the slushing oil composition and thereby are protected against corrosion during subsequent storage and transportation of the steel panels.

Example XIV The additive composition of Example I is used in a concentration of 2% by weight in di-(Z-ethylhexyl) 116 'sebacate marketed under the trade name of Plexol 201. This material is used as a synthetic lubricating oil and the incorporation of the additive therein serves to stabilize the lubricity properties of the lubricant during use under severe operating conditions.

Example XV The additive composition of Example I is used as an additive in soluble oils. Soluble oils vary from homogeneous compositions containing lubricating oil, soap and a small amount of water to emulsions of mineral oil and large amounts of water. These oils are used for cooling and lubricating in the cutting of metals. One percent by weight of the salt described above is incorporated in the soluble oil and serves to stabilize the lubricity properties thereof during use.

We claim as our invention:

1. Lubricating oil containing water and from about 0.01% to about 25% by weight of a mixture of (1) from about 5% to about by Weight of a salt of N-alkyl-l,3- diaminopropane having from about 8 to about 25 carbon atoms in the alkyl and polyoxyethylenated alkylphenol phosphate having from about 6 to about 15 carbon atoms in the alkyl and (2) from about 95% to about 5% by weight of a salt of N-alkyl-l,B-diaminopropane having from about 8 to about 25 carbon atoms in the alkyl and alkyl acid orthophosphate having at least one alkyl group of from about 5 to about 20 carbon atoms.

2. Lubricating oil containing water and from about 0.01% to about 25% by weight of a mixture of (1) from about 5% to about 95% by weight of a salt of N-alkyl- 1,3-diaminopropane having about 8 to about 25 carbon atoms in the alkyl and polyoxyethylenated nonylphenol phosphate and (2) from about 95% to about 5% by weight of a salt of N-alkyl-1,3-diarhinopropane having from about 8 to about 25 carbon atoms in the alkyl and mixed monoand di-isooctyl acid orthophosphate.

3. Lubricating oil containing water and from about 0.01% to about 25% by weight of a mixture of (1) from about 5% to about 95% by weight of a salt of N-tallow- 1,3-diaminopropane and polyoxyethylenated nonylphenol phosphate and (2) from about 95% to about 5% by weight of a salt of N-tallow-1,3-diaminopropane and mixed monoand cli-isooctyl acid orthophosphate.

4. Lubricating oil containing water and from about 0.01% to about 25 by weight of a mixture of (1) from about 5% to about 95% by weight of the neutral salt of N-tallow 1,3 diaminopropane and polyoxyethylenated nonylphenol phosphate and (2) from about 95% to about 5% by weight of the acid salt of -Ntallow-l,3-diaminopropane and mixed monoand di-isooctyl acid orthophosphate.

References Cited by the Examiner UNITED STATES PATENTS 2,285,854 6/42 Downing et a1 25234.7 X 2,848,414 8/58 Chenicek 2S2-32.5 2,961,408 1 1/60 Havely et al. 25232.5 X 3,000,824 9/61 Morway et a1. 25249.8 X 3,004,057 10/61 Nunn "Q 252351 X 3,010,903 11/61 Clarke et al 25249.8 X 3,017,359 1/62 Gottshall et a1. 25232.5 X 3,033,889 5/62 Ohiddix et a1. 25249.8 X 3,079,339 2/63 Cantrell et al 2S2-32.5

DANIEL E. WYMAN, Primary Examiner, 

1. LUBRICATING OIL CONTAINING WATER AND FROM ABOUT 0.01% TO ABOUT 25% BY WEIGHT OF A MIXTURE OF (1) FROM ABOUT 5% TO ABOUT 95% BY WEIGHT OF A SALT OF N-ALKYL-1,3DIAMINOPROPANE HAVING FROM ABOUT 8 TO ABOUT 25 CARBON ATOMS IN THE ALKYL AND POLYOXYETHYLENATED ALKYLPHENOL PHOSPHATE HAVING FROM ABOUT 6 TO ABOUT 15 CARBON ATOMS IN THE ALKYL AND (2) FROM ABOUT 95% TO ABOUT 5% BY WEIGHT OF A SALT OF N-ALKYL-1,3-DIAMINOPROPANE HAVING FROM ABOUT 8 TO ABOUT 25 CARBON ATOMS IN THE ALKYL AND ALKYL ACID ORTHOPHOSPHATE HAVING AT LEAST ONE ALKYL GROUP OF FROM ABOUT 5 TO ABOUT 20 CARBON ATOMS. 